From October blog:

https://all3dp.com/4/prusa-announces...nter-prusa-xl/

However, that’s not all Prusa has in store. The company is also working on “Prusa XL” 3D printer which will have a whopping 400 x 400 x 400 mm build volume and will be based on CoreXY architecture. The company says it will have “a new geared extruder and an improved heatbed — among other things,” but did not elaborate further.